PV1
DC:AC Example: A PV array with a DC STC rating of 5300 watts can be installed on a grid-direct inverter with a max AC output power of 5000 watts. 5300:5000 is within the 1.35:1
1.35:1
Load Side Connection rule for the breaker Example: when making a load side connection in a panel with a 200a main breaker and a 200a bus rating, the maximum backed breaker for the load side interconnection is 40a. (120% of 200a is 240a, so a 40a breaker can be put on the bus)
120%
Load side connections require that the total rating of the breakers supplying power to the busbar to not exceed __________ of the rating. 100% 120% 240a 200a 100a
120%
What is the minimum overcurrent protection for a PV source circuit consisting of modules with a rated short circuit current of 8.8 amps? 10.0, or a common 10amp fuse 13.75, or a more common 15 amp fuse/breaker 8.8, or a common 10amp fuse/breaker 11.3, or a common 11.3 breaker
13.75, or a more common 15 amp fuse/breaker
A crystalline silicon PV module with a maximum power point voltage (Vmp) around 18 volts is likely made up of how many individual PV cells 72 144 12 36 17
36
Preliminary system sizing indicates that the target size for the PV array is 12.6W. If 315W modules are to be used for the array, which design matches the target size? 2 parallel strings of 10 modules in series 2 parallel strings of 15 modules in series 4 parallel strings of 10 modules in series 4 parallel strings of 15 modules in series
4 parallel strings of 10 modules in series
Which of the following equipment allows for module level maximum power point tracking? string inverters central inverter DC to DC converters only Microinverters only Both microinverters and DC-DC converters
Both microinverters and DC-DC converters
At a grid-direct string inverter ungrounded conductors must have a ______________ means to isolate the inverter from all power sources. grounded disconnecting fusing accessing
Disconnecting
A PV array with a DC STC rating of 5300 watts can never be installed connected to a grid-direct inverter with a maximum AC output power of 5000 watts without damaging the inverter. Select one: True False
False
A pyronometer measures temperature. Select one: True False
False
Measuring the solar resource and shade is the only thing to do during a site assessment. Select one: True False
False
Sunlight intensity primarily affects what voltage of a module. Select one: True False
False
The purpose of an inverter is to change alternating current to direct current. Select one: True False
False
The purpose of the solar pathfinder is to measure roof angle. Select one: True False
False
The rating of the overcurrent protection device must be greater than the ampacity of the conductor it protects. Select one: True False
False
When testing the Voc of a module, the correct setting for a digital multimeter is Volt (AC)? Select one: True False
False
True or False: 1 AWG is larger than 1/0 AWG.
False. As number goes down, the diameter/size of the wire goes up
Inverter Output Overcurrent Protection
Inverter rated continuous current X 1.25 = Minimum inverter output
Minimum Series Fuses/Overcurrent Protection in DC PV circuits
Isc X 1.25 X 1.25 (Isc X 1.56) (unit is amps)
A load-side connection for an inverter occurs on a breaker in a similar manner to all other circuits in the home or business. Select one: True False
True
A supply-side connection means the AC output on the Inverter is connected on the utility side of the Main AC service. Select one: True False
True
If a grid-direct PV system has two PV source circuits, overcurrent protection is not normally required on the individual circuit conductors. Select one: True False
True
Irradiance is measure in watts / m2 and is a measure of power. Select one: True False
True
T/F - A PV source circuit carrying 12 amps is appropriately sized with 12AWG THHN
True
The bulk of the solar irradiance reaches a site between 9am-3pm Select one: True False
True
The primary purpose of overcurrent protection (circuit breakers and fuses) is to prevent conductors from overheating and potentially causing a fire Select one: True False
True
True or False: the most common POIs are load-side connections
True
When using DC-to-DC converters on a PV array that will be connected to the grid, an inverter is still required. Select one: True False
True
A string inverter with two MPPTs allows for: Two PV source circuits of different lengths to be connected Two PV source circuits - one to have arc fault and the other to have ground protection Two PV source circuits - one from a 'grounded' array and the other from an 'ungrounded' array.
Two PV source circuits of different lengths to be connected
When two or more PV modules are wired in series, voltage is ______________ in the circuit. equal restricted staggered subtracted additive
additive
A micro inverter is wired to.... An appropriately sized array to a central inverter an individual module groups of lower wattage modules
an individual module
In order to meet _______________ requirements, if utility power shuts down, a grid-direct inverter must also shutdown. peak power demand side anti-islanding consumption
anti-islanding
A PV array is connected to a grid-direct inverter and is operating at STC. The array output should be closest to: a) Voc and Isc b) Vmp and Imp c) Temperature coefficient and nominal voltage thin film
b) Vmp and Imp
Which one of the following does not affect the power output of a PV module? a) sunlight intensity b) inverter efficiency c) cell temperature d) shading e) crystalline structure
b) inverter efficiency
Temperature primarily affects the ____________ of a module. a) flexibility b) voltage c) current d) flux e) ambienotronics
b) voltage
Which of the following terms represents Voc? a) The amount of amperage which a module or array will produce when its positive and negative leads are directly connected together with no load (no resistance) in between. b) The point on the IV curve where the product of voltage times current is the greatest (equaling the most watts). c) The measured voltage, between the positive and negative leads, when a PV module/array is exposed to sunlight but not connected to a circuit (there is infinite resistance between positive and negative).
c) The measured voltage, between the positive and negative leads, when a PV module/array is exposed to sunlight but not connected to a circuit (there is infinite resistance between positive and negative)
At a grid-direct string inverter ungrounded conductors must have a ______________ means to isolate the inverter from all power sources. grounded disconnecting fusing accessing
disconnecting
What are three benefits of microinverters? i. Array can have multiple orientations and tilt angles ii. Fewer inverters to install iii. Individual module output can be monitored iv. Reduced inverter operating temperatures v. Ease of maintenance vi. Maximum power point of each module is tracked
i. Array can have multiple orientations and tilt angles iii. Individual module output can be monitored vi. Maximum power point of each module is tracked
When testing the Voc of a module, what is the correct setting for a digital multimeter i. VDC ii. VAC iii. AAC iv. ADC
i. VDC (voltage DC)
GEC stands for: i. Grounding Electrode Cable ii. Grounding Electrode Conductor iii. Grounding Energy Capacitor iv. Green Electrical Conductor
ii. Grounding Electrode Conductor
The amount of current a conductor can carry is defined as its_______________. i. resistance ii. ampacity iii. AWG iv. volts v. amps
ii. ampacity
The equipment grounding conductor must be___________________. i. bare wire, green, or blue ii. bare wire, green, or green with yellow stripes iii. never bare wire iv. always white v. never green
ii. bare wire, green, or green with yellow stripes
The grounded conductor is a(n) _________________ that is intentionally connected to the grounding system at one point. i. positive conductor ii. current-carrying conductor iii. isolated conductor iv. black wire v. braided conductor
ii. current-carrying conductors Neutral/negative
Additional rapid shutdown equipment is required for _________ installed on a building. i. Microinverters ii. Disconnects iii. String inverters iv. Racking
iii. String inverters
Which of the following doesn't affect variation in solar raditation Time of day Time of year Tilt of the earth cloudiness inverter type
inverter type
When calculating wire size for various circuits, ampacity and voltage drop calculations will often result in different sizes. Which size should be selected? i. Always pick the wire given from the NEC calculation ii. Always pick the wire given from the voltage drop calculation iii. Always pick the smaller (diameter) of the two wires iv. Always pick the larger (diameter) of the two wires
iv. Always pick the larger (diameter) of the two wires
Grid-direct inverters use ____________ to operate the connected array at the highest wattage "knee" of its IV curve. peak patella point tracking maximum power point tracking peak efficiency monitoring Isc / Vor intersect tracking
maximum power point tracking
In a series connection, the positive lead of one module connects to the ____________ lead of the next module. first ground negative neutral positive
negative
When a fuse blows or a circuit breaker trips, it _____________ the circuit, protecting the conductor shorts opens closes energizes
opens
Properly sized and located overcurrent protection devices (OCPD) will: ensure the system voltage doesn't exceed component ratings protect only the PV modules protect a conductor from current exceeding the conductors capacity ensure system regularity
protect a conductor from current exceeding the conductors capacity
Properly sized and located overcurrent protection devices (OCPD) will: ensure the system voltage doesn't exceed component ratings protect only the PV modules protect a conductor from current exceeding the conductors capacity ensure system regularity
protect a conductor from current exceeding the conductors capacity
What is NOT a benefit of grid direct inverters? fewer system components less expensive provides backup power more efficient
provides backup power
